Prediction of Bearing Capacity for Rock-Socketed Under-Reamed Uplift Piles Based on Hoek-Brown Failure Criterion

Piles are often designed to resist uplift actions resulting from wind, wave, earthquake, and underground water in high-rise buildings and long-span bridges. A rock-socketed under-reamed uplift pile can bear larger capacity with better performance, although its theoretical study is lagging behind the application, especially the prediction of bearing capacity. Based on the Hoek-Brown failure criterion of rock, a new simplified calculation formula is deduced according to the similar analysis and prediction method of capacity of under-reamed piles in soil. Two static loading tests were conducted on piles in Zifeng tower in Nanjing. The comparisons were made among predictions resulted from the simplified formula, other empirical methods, and field test results in Zifeng, including other test data in the literature. The results from simplified calculation formula agree well with the test results.